Malignant neoplasms of the liver cause significant morbidity and mortality in the US. Fortunately, for patients with hepatocellular carcinoma or metastatic colorectal carcinoma that is limited to the liver, surgical treatment of the individual hepatic lesions can result in a favorable prognosis. However, surgery is limited to 10% of these patients, and for all others, treatment options are limited. Minimally invasive thermal ablation has the potential to provide a non-surgical treatment option. MRI can provide real-time visualization of treatment devices within the liver. MRI can also potentially ensure adequate heating of target tumor tissue and sparing of adjacent critical organs by providing real-time temperature imaging. This capability would enhance both the effectiveness and safety of thermal therapy. No other imaging modality is capable of providing in vivo temperature maps. Unfortunately, MRI is generally bypassed as a monitoring modality in favor of other modalities such as ultrasound and CT. This is because the promise of robust real-time thermometry for liver ablation has remained an elusive goal due to respiratory motion artifacts. At Stanford, we have been successful in developing MR temperature-mapping techniques suitable for use in minimally invasive treatment of stationary tissues such as the brain and the prostate. We now extend this work to the liver because of its great clinical importance. The major focus will be to develop MR methods that will ensure accurate and precise temperature imaging and to define the achieved accuracy and precision in animal studies. Specifically, we will improve the baseline phase correction with the use of a gated, navigated, multibaseline, volumetric imaging method. These improvements are the key to overcoming the barriers to the use of MR temperature imaging for guiding thermal therapies.